Ecological Risk Assessment of a Metal-Contaminated Area in the Tropics. Tier II: Detailed Assessment

PLoS One. 2015 Nov 3;10(11):e0141772. doi: 10.1371/journal.pone.0141772. eCollection 2015.

Abstract

This study presents data on the detailed evaluation (tier 2) of a site-specific ecological risk assessment (ssERA) in a former smelter area contaminated with metals (Santo Amaro, Bahia, Brazil). Combining information from three lines of evidence (LoE), chemical (ChemLoE), ecotoxicological (EcotoxLoE) and ecological (EcoLoE), in the Triad approach, integrated risk values were calculated to rank sites and confirm the potential risk disclosed with tier 1. Risk values were calculated for the habitat and for the retention functions in each sampling point. Habitat function included the ChemLoE calculated from total metal concentrations. The EcotoxLoE was based on reproduction tests with terrestrial invertebrates (Folsomia candida, Enchytraeus crypticus, Eisenia andrei), shoot length and plant biomass (Avena sativa, Brassica rapa). For the EcoLoE, ecological parameters (microbial parameters, soil invertebrate community, litter breakdown) were used to derive risk values. Retention function included the ChemLoE, calculated from extractable metal concentrations, and the EcotoxLoE based on eluate tests with aquatic organisms (Daphnia magna reproduction and Pseudokirchneriella subcapitata growth). Results related to the habitat function indicated that the metal residues are sufficient to cause risk to biota, while the low metal levels in extracts and the general lack of toxicity in aquatic tests indicated a high soil retention capacity in most sampling points. Integrated risk of tier 2 showed the same trend of tier 1, suggesting the need to proceed with remediation actions. The high risk levels were related to direct toxicity to organisms and indirect effects, such as failure in the establishment of vegetation and the consequent loss of habitat quality for microorganisms and soil fauna. This study shed some light on the selection of tools for the tier 2 of an ssERA in tropical metal-contaminated sites, focusing on ecological receptors at risk and using available chemical methods, ecological surveys and ecotoxicity tests.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Avena / growth & development*
  • Brassica rapa / growth & development*
  • Brazil
  • Environmental Pollution / adverse effects*
  • Invertebrates / growth & development*
  • Metals / toxicity*
  • Tropical Climate*

Substances

  • Metals

Grants and funding

The study was partially supported through two PhD grants to JCN, from Program Alban (Brazil; E05D058118BR) and Fundação para a Ciência e a Tecnologia (FCT, Portugal; SFRH/BD/28796/2006) and through Ciência 2007-FSE and POPH and QREN funds (FCT, Portugal). EMS and MAN acknowledge receiving a grant from the Brazilian Research Council (CNPq). The work was supported by Department of Life Sciences own funds and facilities. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.